JPH0515567Y2 - - Google Patents

Description

[Detailed explanation of the invention] A. Purpose of the invention (1) Industrial application field The invention consists of a pair of vertically aligned cylinders formed in the engine body, and a carburetor placed at the top of one side of the engine body. Concerning improvements to vertical internal combustion engines.

(2) Prior Art This type of internal combustion engine has a crankshaft arranged in a vertical direction, and is therefore widely used in outboard motors and the like that have a drive shaft connected to the crankshaft in a vertical direction.
In this case, the carburetor is disposed at the upper part of one side of the engine body in order to smoothly flow the air-fuel mixture from the carburetor into each cylinder. Further, a carburetor having a single intake passage is used.

(3) Problems to be solved by the invention According to the above-mentioned conventional configuration, the single intake passage of the carburetor is close to the upper cylinder for a pair of cylinders, so the cylinder and intake passage are located at the upper part. The intake passage connecting the lower cylinder and the intake passage is formed relatively short, but the intake passage connecting the lower cylinder and the intake passage is formed relatively long. As a result, there was a large difference in the length of the two intake passage systems from the carburetor to each cylinder.
This difference causes intake interference between the pair of cylinders, making it difficult to obtain satisfactory output performance of the engine.

The present invention was devised in view of the above circumstances, and its purpose is to provide a simple and effective vertical internal combustion engine in which the intake passage system of each cylinder can be formed to approximately the same length without changing the arrangement of the carburetor. do.

B. Structure of the invention (1) Means for solving the problem In order to achieve the above object, the present invention incorporates a carburetor, which has a pair of intake passages arranged horizontally and approximately parallel to the cylinder, into the engine body. The air intake path on the side far from the engine body is connected to the upper cylinder through the first intake path, and the air intake path on the side closer to the engine body is connected to the lower cylinder through the second intake path. It is characterized by communicating.

(2) Effect When the intake path of the carburetor that is far from the engine body is connected to the upper cylinder through the first intake path, and the intake path that is close to the engine body is connected to the lower cylinder through the second intake path, The first and second intake passages have approximately equal lengths, and the lengths of the two intake passage systems from the carburetor to each cylinder can be made approximately equal.
As a result, intake air interference between both cylinders can be prevented or significantly reduced.

(3) Embodiment Hereinafter, an embodiment in which the present invention is applied to an outboard motor will be explained with reference to the drawings. First, in FIG. A type internal combustion engine 3 is mounted, and an engine cover 4 that covers this engine 3 is installed.
are bound. A vertically extending crankshaft 5 of the internal combustion engine 3 is connected to a drive shaft 6 that runs longitudinally within the extension case 2 . A gear case 8 that pivotally supports the propeller 7 is attached to the lower part of the extension case 2, and a gear transmission 9 that rotates the propeller 7 forward or reverse in response to the rotation of the drive shaft 6 is attached to the gear case 8. be accommodated. Therefore, when the crankshaft 5 rotates, its rotational torque is transmitted to the propeller 7 via the drive shaft 6 and gear transmission 9, allowing it to rotate forward or reverse.

The extension case 2 is steerably connected to a swivel case 11 via a vertical swivel shaft 10, and the swivel case 11 is connected to the hull 1.
It is connected via a horizontal pivot 14 to a stern bracket 13 which is clamped to the second stern plate 12a so that it can be tilted up.

In FIGS. 2 and 3, the engine body 20 of the internal combustion engine 3 includes a pair of cylinders 21 arranged vertically.
₁ , 21 ₂ , a crank case 24 connected to one end of the cylinder block 23, and a cylinder head 25 connected to the other end of the cylinder block 23. The head 25 is placed toward the rear of the hull 12. The crankshaft 5 is rotatably held between a cylinder block 23 and a crankcase 24, and is also connected to cylinders 21 ₁ , 2
The connecting rods 26 1 and 26 ₂ are connected to pistons _{22 1} and 22 ₂ which slide into the pistons 1 ₂ , respectively.

Intake ports 27 ₁ , ₂ of cylinders 21 ₁ , 21 2
7 ₂ are arranged vertically in the same way as the cylinders 21 ₁ and 21 ₂ and open on one side of the cylinder head 25, and the exhaust ports 28 ₁ and 28 ₂ are connected to the cylinder head 2.
Opens on the bottom surface of 5. These intake and exhaust ports 27
₁ , 27 ₂ , 28 ₁ , 28 ₂ Suction and exhaust valves 2 that open and close
The cylinder head 25 is provided with valves 9 ₁ , 29 ₂ , 30 1 , 30 ₂ and a known valve operating device ₃₁ for driving these intake and exhaust valves 29 ₁ , 29 ₂ , 30 ₁ , 30 ₂ . A camshaft 32 of this valve train 31 is supported by the cylinder head 25 and is driven from the crankshaft 5 via a belt type timing transmission 33.

An intake manifold 34 connected to the intake ports 27 ₁ and 27 ₂ is provided on one side of the cylinder head 25.
are connected by a plurality of bolts 35, 35, .

The carburetor 36 includes a pair of intake passages _{37 1 ,} 37 ₂ extending substantially parallel to the cylinders _{21 1} , 21 ₂ .
₁ and 21 ₂ , that is, in the horizontal direction. Each of the intake passages 37 ₁ and 37 ₂ is independent, and internally there are choke valves 39 ₁ and 39 ₂ on the upstream side and throttle valves 40 ₁ and 40 ₂ on the downstream side with the bench lilies 38 ₁ and 38 ₂ in between. Although it is installed, the intake path 3
A common intake chamber 42 having a filter screen 41 is provided at the inlets of 7 ₁ and 37 ₂ .

The intake manifold 34 includes a pair of first and second intake passages 43 ₁ and 43 ₂ , and the first intake passage 43 ₁ connects the intake passage 37 ₁ on the side far from the cylinder block 23 to the upper cylinder 21 ₁ . Intake port 27
The _second intake passage 43 ₂ is formed so as to communicate the intake passage 37 ₂ on the side closer to the cylinder block 23 with the intake port 27 ₂ of the lower cylinder 21 ₂ .

The exhaust ports 28 ₁ and 28 ₂ communicate with the interior of the extension case 2 via an exhaust manifold (not shown) so that underwater exhaust can be performed.

Next, the operation of this embodiment will be explained. vaporizer 36
The intake passage 37 ₁ far from the cylinder block 23 is connected to the upper intake port 27 _{1 via the first intake passage 43 1 .}
Also, the intake passage 37 near the cylinder block 23
₂ to the lower intake port 2 via the second intake passage 43 ₂
7 ₁ respectively, both intake passages 43 ₁ , 43
₂ have approximately the same length with each other, so the intake passage 37
The lengths of the two intake passage systems from the upstream ends of the intake ports 27 _{1 and} 37 ₂ to the downstream ends of the intake ports 27 1 _and 27 2 can be made approximately equal. As a result, during the operation of the engine 3, there is no intake air interference between the cylinders 21 ₁ and 21 ₂ , and therefore the air-fuel mixture can be equally supplied to the cylinders 21 ₁ and 21 ₂ , resulting in improved output performance of the engine 3. It is possible to improve the

C. Effects of the invention As described above, according to the invention, a carburetor having a pair of intake passages arranged horizontally and substantially parallel to the cylinder is disposed at the upper part of one side of the engine body, and the carburetor is arranged at the upper part of one side of the engine body. With a simple structure in which the intake passage is connected to the upper cylinder via the first intake passage, and the intake passage closer to the engine body is connected to the lower cylinder via the second intake passage, the intake passage system of both cylinders is improved. Since the lengths can be made substantially equal, interference between the intake air of both cylinders can be prevented, and the air-fuel mixture can be equally supplied to both cylinders, contributing to an increase in the output of the engine. Moreover, since each intake passage of the carburetor is arranged at the upper part of one side of the engine body, the air-fuel mixture flows smoothly from each intake passage into the corresponding cylinder.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention. Figure 1 is a side view of an outboard motor equipped with the internal combustion engine of the present invention, and Figure 2 is a side view of the internal combustion engine with the carburetor shown in a longitudinal section. FIG. 3 is a cross-sectional view taken along the line - 3 in FIG. 2. 3...Internal combustion engine, 20... Engine body, 21 ₁ ,
21 ₂ ... Upper and lower cylinders, 23 ... Cylinder block, 24 ... Crank case, 25 ... Cylinder head, 27 ₁ , 27 ₂ ... Intake port, 3
4... Intake manifold, 36... Carburetor, 37
₁ , 37 ₂ ... Intake path, 43 ₁ , 43 ₂ ... First and second intake path.

Claims (1)

[Scope of utility model registration request] In a vertical internal combustion engine in which a pair of vertically arranged cylinders are formed in the engine body, a carburetor having a pair of intake passages arranged horizontally and approximately parallel to the cylinders is disposed at the upper part of one side of the engine body. The intake path on the far side is connected to the upper cylinder via the first intake path, and the intake path on the side closer to the engine body is connected to the second intake path.
A vertical internal combustion engine characterized by each cylinder communicating with the lower cylinder through an intake passage.